The prior art is replete with single and multiple wheeled body attached load carriers as can be seen by reference to the following U.S. Pat. Nos. 3,550,997; 4,171,139; 2,401,986; 3,144,014; British Pat. No. 1,604,449 and German Pat. No. 298,324.
The above cited prior art share many structural similarities; in that they all disclose a wheeled tubular framework associated or attached to a portion of the users anatomy. In addition, all of these devices are designed to accomplish the same function, which is the extended capability of the user to travel greater distances carrying more weight than would be possible in the absence of mechanical assistance.
It should not come as a surprise therefore that the subject matter of the present invention also incorporates some of the more basic structural components of the prior art devices in its own unique construction. What is surprising about the present invention is the fact that the prior art is so relatively crowded and to date no one has employed an integrated assembly approach to this area of technology and produced a "mule" or user propelled wheeled load carrier having the features found in the present invention.
Even though the prior art involves a well recognized basic principal and technology; the structures represented in the patent literature are deficient in a number of respects, that they share both individually and in common with one another.
The most common shared deficiencies in the prior art devices are: lack of stability; inadequate load capacities; absence of brake mechanisms; lack of stand alone capability; manually assisted lateral maneuvering requirements; high profiles when the user is in a prone position; and, mid-body user contact.